goiby



. l.. CULBY.

SPARK PLUG.

m Uu/Miur.' min MAH. m luf/uA 1,374,281. Patented Apr. 12, 1921.

2 SINUS SHEE l.

UNITED sfrn'res PATENT oFFIcs. i

ERNEST L. GOLY, F PUEBLO, COLORADO.

esami-rms.

To all whom it may concern:

Be it known that I, Ennns'r L. (loner, a citizen of theUnited States,residing at Pueblo, county of Pueblo, State of Colorado, have inventednew and useful Improvements in Spark-Plugs, of which the following 1s aspecification. Y

This invention pertains to spark plugs, and. particularly to theelectrode and insu-` lating structure as 'embodied in such plugs. 'Anobject of the invention is to provide a spark plug embodying 4meanswhich will prevent the `formation of a "hydrocarbon fluid film to shortcircuit-across the insulating material,` andfalso to prevent carbon fromcoating the same Vwhich will result V1n short circuitin .the pluv. 1 Afurther o 'ect resides in arrangingobliquely dispose '.b'aiiles at theinnerend of the orilice of the shell of the spark pluv as guards againstthe entrance of hydrocar on Huid or carbn laden ases. i U

Another object .resi es in so-constructing the central electrode that itclears the baffles and is at the same .time sufliciently-spaced fromtheshell structure to insure against4 short circuitingn `and consequent`sparking except across the spark-gap. Yet another object is to provideavspark plug embodyingV the features above ,stated which can beeiciently and cheaply. manufactured, andwhich presents the parts in suchrelatonthat there is little possibility of the spark plugfbecoming foued, short circuited through carbon deposits, or otherwise rendereduntfor the purpose intended or inoperative in use. r p c 'Y With theseand other objects4 in vlew which will be apparent from the-drawings,specification and claims, this invention includes certain novel featuresof construc tion and combination of `parts which will now be set forth.l

In the drawingsz" j Figure lis a view in elevation `of'a s ark plugconstructed after the manner o my invention. F ig. 2 is a iviewvinvertical section through the plug. y y y 1 v Fig. 3 is a view in4elevation of the sparking. end ofthe plug; N Fig. 4 is a'transversesectional vlewV on line 4`40ffFig. 2; j Fig. 5 isa'view4similar to Figxl t'akeno'n limsi-5".4 Y y "Fig, G is an enlargedperspective vievvof Specification 4cf Letters Patent.

.ba es.

:Patented apr. 12, 1921.

Application filed March 16, 1920. Serial No. 366,285.

the inner end of the centralinsulator to better show the formation ofthe central electrode.

Fig. 7 is a fragmentary sectional view showing a slightly modifiedconstruction ofv plu `and the use of a greater number of Fig. 8 is alviewsimilar to Fig. 7 Vshowing an ada tation suitable forplugs having ashorts ell. Fig. 9 is a view in elevation of the sparkinend of the plugillustratedgin Fig. 8.

1g. 10 is a perspective view of the' sleeve by -Whic'h' the bellies aremounted in the last mentioned adaptation.

In themain embodimentll -have shown a shell l of the type havinganextension 2. This shell is bored to provide' a central chamber 3at'its inner end whchis received 1n the engine cylinder, and at'itsouter end is internally screw threaded to take packing gland 4. f l Acentral insulator 5, of `porcelain or other suitable material, is fittedwithin the shell to' rest n cn a shoulder `6 and is'held in place by pac'ng Ygland/4., a suitable packerably extended at oblique angles fromtheir i point of startingfon the outer wall to 1their innerencls,theangle of inclination being toward the open end of chamber Sub stantiallysemi-circular baiiiemembers 1l and 12 are secured in these slits andare-thus presented as .obliquel set ballles guardin the openend of chamer 3 the extension o the inner edge of each baliie member past a medialline ositivel precluding the direct ilow of iui 'from t e enginecylinder into `,the `body `of the chamber to precipitate carbon or otherdeposits-around and upon the central electrode.

By this arrangement of thebailies the opening from the body of thechamber 3 t0 the outer end is made circuitous, and to suit thiscondition central electrode 7 is bent angularly to have a zigzag form,as best shown in Fig. (3, in that part extending beyond the centralinsulator. By this formation of the central electrode the bailles 11 and12 are cleared when the parts of the plug are assembled, and a sparkingterminal 13 is presented at the open end oi? chamber 3, this sparkingterminal being near the center.

The shell 1 and its extension 2 are the ground structure of the plug,and care is oi course to be exercised in the formation of the centralelectrode 7 so that it clears this ground structure at all points fromcentral insulator 5 to its sparking terminal 13 that all danger of shortcircniting is precluded. This sparking terminal 13 might be extendedsufliciently to provide a spark rap directly between the terminal andthe sie l structure, however it is preferable that a ground electrodeterminal 14 carried by the shell structure be formed to extend inproximity to sparking terminal 13 to thus more nearly center the sparkgap with respect to the open end of chamber 3.

Theparts are assembled after-the manner shown in Figs. 1 and 2,- and theplug is inserted in the usual manner in the opening of the cylinder, thechamber 3 then opening into the explosion chamber. The plug is connectedin the usual ignition circuit and when current is passed through thiscircuit the s ark will jump the gap between termina s 13 and 14. Thearrangement of the baffles set on an oblique angle out from oppositepoints in the shell presents aA guard against the inrush of hydrocarbonor other fluid from the cylinder and thus with my improved spark plugthere is little likelihood of the formation of a fluid film or of acarbon coating to short circuit across theynsulating material. Thebaffle members 11 and 12 are made up of several sheets of mica combinedto vive the requisite strength, or are made up o other suitableinsulating material, and thus short circuiting from the celpltralelectrode to these bales 1s not possi c.

With the modified construction as shown in Fig. 7 the shell 15 has asomewhat longer extension 16, than is shown in the main embodiment, andwith this form the four ballie members 17, 18, 19, and 20 are employed.These baille members are arranged to extend alternately from oppositepoints within the chamber of extension 16, and due to the staggeredAarrangement a double guard is provided in the open end of the chamber.The central electrode 21 is bent to a -zigzag form to clear theseveral-baffles and a ground s arking terminal- 22 carried by extension16 1s disposed adjacent the terminal 23 of the central electrode. It ispreferable that at least two baille members be emplo ed as Where two areused and each extends past a medial line the direct passage into thechamber is closed. It will be appreciated that three bailie membersmight be used or that a rreater number than four may be employe ln theadaptation in Figs. 8, 9, and 10, the shell 24 oi the spark plug isrelatively short and has con'iparatively no extension beyond thethreaded portion, it thus being inexpedient to cut into or slit theshell to receivc the baflles, and to overcome this difficulty I providean inner bushing 25 by which baffles 26 and 27 are mounted. The shell 24is reamed or otherwise enlarged in the central chamber as at 28, and thebushing 25 is litted therein. This bushing may be secured in place inany manner, and can be fitted removably in place if desired. The centralelectrode 29 is substantially of the same form as electrode 7, shown inFics. 2 and 6, however the central insulator will be shorter in thatportion extendinr within the chamber of the shell. Ground electrodeterminal 30 is formed in much the same manas terminal 14.

While thc baiile members might be secured in place in any desiredmanner, I have found it expedient to x these members and clamp the samein place, substantially as show-n in Fig. 1,0, by forming a line ofcenter nnch holes 31 in the metal adjacent each allie member to expandthe member to grip and clamp the same against movement. This same methodof securement may be employed in fixing the baffle members in theextension of thesleeve, o1 some other method accomplishing the desiredresult can be carried out.

l-Vhile in the foregoing, I have shown and described onlycertainspecific embodiments and have referred to possible modifications, itwill be appreciated that in practice -other changes in the constructionand arrangement of the arts can be resorted'to, in 4View of which I onot wish to be limited to the exact disclosure but to such embodiments'of my invention falling. within thev scope` of the appended claims.

I claim:

1. A spark plug including with a shell having a chamber at its innerend, a plurality of obliquely arranged bales in sta gered relationwithin said chamber wit their inner edges extending past the axialcenter of said chamber and angularly toward the open end thereof.

.21A spark plug including with a shell having a chamber at tsinner end,aplurality of obliquely arranged baffles in sta v said chamber, and aelectrode member Vbent to zigzag form to clear said baiiies and toextend from the end of said chamber.

3. A spark plug including with a shell having a chamber at its innerend, a plurality of obliquely arranged substantially semi-circular balesof insulating material in staggered relation Within said chamber with teir inner edges extending past the axial center of saidchamber andangularly toward the open end thereof.

4. A spark plug including with a shell having a chamber at its innerend, a plurality of obliquely, arranged substantially semi-circularbaiiles of insulatin material in staggered relation within said chamberwith their inner edges extending past the axial center of said chamberand angularly toward the open end-thereof, a central e1ec trode bentangularly to a zigzag form to clear said baffles and project a terminalfrom ound electrode terminal carried by said shell extended adjacentsaid projecting terminal.

5. A spark fplug including with a shell having an ori ce lat its innerend, a sleeve received in said orifice and a plurality of op ositel disused su stantially semi-circu ar ha es o insulatin material mountedwithin said sleeve with t eir inner e ves extending past the axialcenter of said orice and obliquely at an angle toward the open endthereof.

6. A' spark plug including with a shell having Aan orifice at its innerend and having slits formed through opposite sides thereo in staggeredrelation extendin past the axial center of said orifice and obtiiquelydisposed an larly toward the open end thereof, and aiiie members fittedwithin said Vslits and held in place by a line of center punchindentations formed on the outer side of the shell adjacent the metalthereof against said baiile members Intestimony whereof, I allix mysignature.

ERNEST L. COLBY.

